Nicotinamide N-methyl transferase and cancer-associated thrombosis: insights to prevention and management

Nicotinamide metabolism is important in carcinogenesis. Nicotinamide affects the cellular methyl pool, thus affecting DNA and histone methylation and gene expression. Cancer cells have increased expression of nicotinamide N-methyl transferase (NNMT), the key enzyme in nicotinamide metabolism. NNMT contributes to tumor angiogenesis. Overexpression of NNMT is associated with poorer prognosis in cancers. Additionally, NNMT can contribute to cancer-associated morbidities, such as cancer-associated thrombosis. 1-methylnicotinamide (1-MNA), a metabolite of nicotinamide, has anti-inflammatory and antithrombotic effects. Therefore, targeting NNMT can affect both carcinogenesis and cancer-associated morbidities. Several antitumor drugs have been shown to inhibit NNMT expression in cancer cells. Implementing these drugs to reverse NNMT effects in addition to 1-MNA supplementation has the potential to prevent cancer-associated thrombosis through various mechanisms. The yin and yang of NNMT activity. Nicotinamide and 1-MNA have anticancer and anti-inflammatory properties. Increased activity of NNMT will lead to excretion of nicotinamide and 1-MNA. In the process of metabolizing nicotinamide, homocysteine is produced, which has thrombotic properties.